The present invention relates to a radiographic image capturing system.
Various kinds of radiographic images, which are represented by an X-ray image captured by using X-ray radiation, have been widely employed for the purpose of diagnosing a disease or the like. This kind of medical radiographic images as abovementioned have been captured by using a screen film. However, in order to promote the digitalization trend of the radiographic image, the CR (Computed Radiography) apparatus that employs a photostimulable phosphor sheet had been developed, and in recent years, there has been developed such the radiographic image capturing apparatus that employs the radiation detecting elements arranged in a two-dimensional pattern for detecting the irradiated radiation so as to acquires the digital image data representing the radiographic image captured.
The abovementioned radiographic image capturing apparatus has been widely known as the FPD (Flat Panel Detector), and framed as an exclusive-use type radiographic image capturing apparatus in which the FPD was integrally equipped into the supporting base (for instance, set forth in JP3639750, Japanese Patent Gazette). However, in recent years, a portable type radiographic image capturing apparatus, which accommodates the radiation detecting elements, etc. inside its housing so as to make it portable, has been developed and put into a practical use (for instance, set forth in Tokkai 2006-058124 and Tokkaihei 6-342099, both are Japanese Patent Application Laid-Open Publications).
Further, as the radiographic image capturing apparatus, there have been developed various kinds of apparatuses, including: the direct-type radiographic image capturing apparatus in which the detecting elements generates electric charges corresponding to the radiation amount of X-ray, etc. irradiated thereon, so as to directly convert the generated electric charges to the electric signals; an indirect type radiographic image capturing apparatus in which the scintillator or the like converts the irradiated radiation to an electromagnetic wave having another wavelength, such as a visible light, etc., and then, the photoelectric converting elements, such as photodiodes, etc., generates electric charges corresponding to the energy intensities of the electromagnetic wave irradiated thereon, so as to convert the electric charges to the electric signals; etc.
In this connection, hereinafter in the present specification, each of the terms of the “detecting elements” to be employed in the direct-type radiographic image capturing apparatus and the “photoelectric converting elements” to be employed in the indirect-type radiographic image capturing apparatus is defined as a term of “radiation detecting elements”.
Further, in the radiographic image capturing apparatus, for instance as shown in FIG. 5 detailed later, a plurality of radiation detecting elements 7 is arranged in a two-dimensional pattern on a detecting section P, so as to form a two-dimensional detecting area thereon.
Incidentally, when the radiographic image capturing operation is conducted by employing such the radiographic image capturing apparatus as abovementioned, even if the same amount of radiation is irradiated onto each of the radiation detecting elements 7, values of data sets D, respectively read from the radiation detecting elements 7, are not necessary same as each other, since the sensitivities of the radiation detecting elements 7 are usually different from each other.
To overcome such the drawback, the, arithmetic calculation processing is applied to each of the data sets D, for instance, by multiplying the value of each of the data sets D by a gain correction value G, as indicated by Equation (1) shown in the following, so as to equalize the different values of the data sets D, read from every one of radiation detecting elements 7 when the same amount of radiation is irradiated onto each of the radiation detecting elements 7, at a uniform value (for instance, set forth in Tokkai 2010-112866, Japanese Patent Application Laid-Open Publication, etc.).D*=log {G×(D−O)}  (1)
In this connection, in Equation (1), “D*” represents the final image data that is acquired by applying the image processing to the data sets D read from the radiation detecting elements 7. Further, “O” represents offset data sets included in the data sets D and caused by dark electric charges generated by the thermal excitations or the like due to heat generated by the radiation detecting elements 7 itself. Further, the offset data sets O are usually acquired every time when the radiographic image capturing operation is conducted.
Further, although, according to the Equation (1), only the well-known and general purpose image processing is to be applied to the data sets D, in practice, other than the gain correction and/or the offset correction processing abovementioned, the various kinds of image processing, such as a normalize processing, a gradation correction processing corresponding to the image capturing portion and conditions, etc., are applied to the data sets D in order to acquire the final image data D*.
In order to acquire the final image data D* to be employed for diagnosing purpose by applying appropriate image processing to the data sets D read from the radiation detecting elements 7, correction data, such as the gain correction value G for each of data sets D, etc., is required in regard to every one of radiation detecting elements 7. In this connection, hereinafter, the correction data, such as the gain correction value G, etc., is generally represented by correction data sets “α”.
Further, generally speaking, based on the data sets D (and offset data sets O) that are acquired by uniformly irradiating a predetermined amount of radiation, serving as parallel light, onto a radiation incident surface R (refer to the schematic diagram shown in FIG. 1, detailed later) of a radiographic image capturing apparatus while avoiding the influence of the shading unevenness of the irradiated radiation amount, just before the radiographic image capturing apparatus is shipped from the manufacturing factory (in other words, at the time of the factory default setting operation), each of the correction data sets “α” is established in regard to each of the radiation detecting elements 7, so that the values of the final image data D* calculated according to the Equation (1) are made to be same as each other allover the radiation detecting elements 7.
Conventionally, any one of various types of radiation sources is installed in the radiation image capturing room in which the radiographic image capturing apparatus is actually operated. Further, according to a certain type of radiation source, for instance, an amount of radiation to be irradiated onto the radiation incident surface R of the radiographic image capturing apparatus increases at a central portion of the radiation incident surface R, while decreases at a peripheral section of the radiation incident surface R. Still thither, even if the same radiation source is employed, the difference between the radiation amounts of the central portion and the peripheral section varies depending on the distance between the position at which the radiation source is fixed and that of the detecting device (subject under inspection).
Further, sometimes, the radiation irradiated from the radiation source would exhibit a shading unevenness (irradiation unevenness) inherent to the radiation source concerned. Accordingly, generally speaking, the radiation characteristic in relation to the radiographic image capturing apparatus differs for every radiation source installed into the radiation image capturing room.
Still further, conventionally, in such the establishment that has employed the screen/film method, the aforementioned difference between the radiation amount at the central portion and that at the peripheral section has resulted in the density difference on the finished film. Accordingly, there has been such a historical circumstance that the diagnosis resolution capability has been established on the premise that the finished film naturally includes such the density difference, as the result of the long year diagnosing history being inherent to every establishment. Therefore, it is hardly to say that the gain adjustment processing for cancelling the difference between the radiation amount at the central portion and that at the peripheral section, so as to make the radiation characteristic to be flat, is always appropriate.
Yet further, conventionally, in the establishment that employs the CR method, since factors of the shading unevenness reside in the radiation source, the phosphor plate and the reading device, respectively, in the case that the shading unevenness correction processing is implemented at the former stage before the output gradation processing is applied, it is necessary to implement a new normalization processing for the FPD use in this former stage, and therefore, it becomes necessary to introduce a new image processing apparatus.
Accordingly, generally speaking, when the radiographic image capturing apparatus is introduced into the radiation image capturing room, the correction data sets “α”, respectively established for the radiation detecting elements 7 at the time of the factory default setting operation as aforementioned, are readjusted so as to fit to the actual operation to be conducted in every establishment (diagnosis resolution capability), corresponding to the radiation characteristic of the radiation source currently installed into the radiation image capturing room, the image processing conditions, etc.
In this connection, hereinafter, in order to distinguish the correction data sets, such as the gain correction value G, etc., which are to be newly established at the time when the radiographic image capturing apparatus concerned is introduced into the radiation image capturing room, from the correction data sets “α” established at the time of the factory default setting operation, the newly established correction data sets are represented by correction data sets “α*”. Further, in order to clarify the difference between the correction data sets “α” and the correction data sets “α*”, hereinafter, these are defined as first correction data sets “α” (also referred to as first α-correction data) and second correction data sets “α*” (also referred to as second α*-correction data), respectively.
In the above case, based on the data sets D that are acquired by irradiating the predetermined amount of radiation, in accordance with the radiation characteristic of the radiation source installed in the radiation image capturing room concerned, onto the radiation incident surface R of a radiographic image capturing apparatus, etc., each of the second correction data sets “α*” is newly established in regard to each of the radiation detecting elements 7, so that the values of the final image data D* calculated according to the Equation (1) are made to be same as each other allover the radiation detecting elements 7.
In other words, the first correction data sets “α” is to be employed for making the values of the final data sets D* same as each other allover the radiation detecting elements 7 when the radiation, serving as parallel light, is irradiated onto a radiation incident surface R at the time of the factory default setting operation, and is to be derived from the characteristics of the radiographic image capturing apparatus itself; such as a conversion efficiency in the radiation detecting elements 7 for converting the radiation to the electric charges, a reading characteristic of a reading electric circuit (not shown in the drawings), etc.
Conversely speaking, in order to acquire the first correction data sets “α” originated from the characteristics of the radiation detecting elements 7 itself; the radiation roughly formed as parallel light is irradiated onto the radiographic image capturing apparatus at the time of the factory default setting operation.
On the other hand, the second correction data sets “α*” is such correction data that is derived from the radiation characteristic of the radiation source currently installed into the radiation image capturing room, the image processing conditions, etc., in addition to the abovementioned characteristics being inherent to the radiographic image capturing apparatus.
Accordingly, with respect to the first correction data sets “α”, one set of correction data is established for every one of the radiation detecting elements 7 of the radiographic image capturing apparatus, while, with respect to the second correction data sets “α”, one set of correction data is established for every one of the radiation sources respectively installed into the radiation image capturing rooms provided in, for instance, a hospital, etc. As a result, a number of second correction data sets “α*” established for the radiographic image capturing apparatus concerned becomes equal to the number of radiation sources being capable of irradiating radiation onto the radiographic image capturing apparatus concerned.
Incidentally, under the circumstances as abovementioned, for instance, in such a case that the radiographic image capturing apparatus should be returned to the factory or the like to fix it, due to the fact that the radiographic image capturing apparatus installed into the radiation image capturing room has malfunctioned, or due to the other reason, it is preferable that another radiographic image capturing apparatus is temporarily provided as the replacement of the radiographic image capturing apparatus concerned during the fixing term thereof
In the abovementioned case, although first correction data sets “β” (hereinafter, also referred to as first β3-correction data), such as the gain correction value G, etc., have been established in advance with respect to the other radiographic image capturing apparatus of the replacement use at the time of the factory default setting operation, when introducing the concerned apparatus of the replacement use into the radiation image capturing room, it is necessary to newly reestablish second correction data sets “β*” (hereinafter, also referred to as second β*-correction data) in order to make it in conformity with the radiation characteristic of the radiation source currently installed into the radiation image capturing room. In this connection, hereinafter, in order to distinguish the first correction data sets, etc. of the other radiographic image capturing apparatus of the replacement use from the first correction data sets “α”, etc. of the original radiographic image capturing apparatus, the first correction data sets, etc. of the former is represented by the first correction data sets “β”, etc.
If the other radiographic image capturing apparatus of the replacement use were continuously operated in the radiation image capturing room from now on, it would be acceptable for the radiation technologist or the like to established the second correction data sets “β*” thereof. However, in reality, it is very cumbersome work for the radiation technologist or the like to purposely established the second correction data sets “β*” of the other radiographic image capturing apparatus of the replacement use, which will be replaced again by the original radiographic image capturing apparatus. Further, when a plurality of radiation sources is respectively installed into a plurality of radiation image capturing rooms, it becomes very troublesome work for the radiation technologist or the like to establish the second correction data sets “β*” for each of the plurality of radiation sources.
On the other hand, as indicated by the schematic diagram shown in FIG. 7, in such a case that a radiation image capturing room Ra is coupled to a console C through a network N, for instance, it is assumed that the radiation technologist or the like declares that he will use a radiation image capturing room Ra1 and another radiation image capturing room Ra2 by operating a console C1 In this case, the console C1 is correlated with the radiation image capturing room Ra1 and the radiation image capturing room Ra2.
Then, during the time when the radiation image capturing operation is currently performed in the radiation image capturing room Ra1, for instance, even if the other radiation technologist or the like intends to conduct the setting operation of the second correction data sets “β*” in regard to the radiographic image capturing apparatus of the replacement use, there has arisen such a problem that, due to the busy status of the console C1 for performing the radiation image capturing operation, it is impossible for the concerned personnel to conduct the setting operation of the second correction data sets “β*” until the busy status of the console C1 is eliminated.